In response to increases in the sizes of substrates, such as wafers for the fabrication of semiconductor devices and glass substrates for the fabrication of flat panel displays, process uniformity across the entire area of a substrate is increasing in importance as an issue. In order to overcome this, showerheads are generally used as gas supplying means in thin-film deposition processing, etching processing, and the like.
In this case, a sufficient amount of gas must be dispersed in a lateral direction, such that the gas may be uniformly injected from the entire area of a showerhead. For this, showerhead configurations each having dispersing fins protruding upwardly from an intermediate plate within a showerhead body have been proposed in Korean Patent Nos. 10-0972801 and 10-0972802.
FIG. 1 to FIG. 3 illustrate related-art showerheads having dispersion pins, substantially identical to those disclosed by Korean Patent Nos. 10-0972801 and 10-0972802 except for reference numerals.
FIG. 1 illustrates a showerhead of the related art. As illustrated in FIG. 1, the interior space of a showerhead body 100 is divided into two spaces, i.e. a dispersion chamber 110 and a distribution chamber 120, by an intermediate plate 150 extended in a lateral direction. The intermediate plate 150 has a plurality of connecting holes 171 extended in the top-bottom direction. Dispersion pins 160 are fitted into the connecting holes 171.
The body 100 has injection holes 170 penetrated through the bottom. A gas supply part 130 is disposed within the dispersion chamber 110.
A flow of gas introduced through the gas supply part 130 toward the central portion of the dispersion chamber 110 in the longitudinal direction collides with the intermediate plate 150, and is subsequently dispersed in a lateral direction, i.e. outwardly from the central portion.
The dispersion pins 160 are intended to accelerate the lateral dispersion. It is preferable that gaps g1 between the upper faces of the dispersion pins 160 and the ceiling of the body 100 are sufficiently small compared to the length of the dispersion pins 160 protruded.
Gas supplied to the showerhead body 100 is uniformly dispersed in the lateral direction within the dispersion chamber 110 for a short period of time, influenced by the dispersion pins 160, and is subsequently uniformly introduced to the distribution chamber 120 below the dispersion chamber 110 through the dispersion pins 160. After the gas is more uniformly distributed within the distribution chamber 120, the gas having a uniform pressure is injected downwardly toward a substrate (not shown) through the injection holes 170.
However, the foregoing showerhead of the related art requires spacers 180 to be disposed within the dispersion chamber 110 in order to uniformly maintain the gap g1 and firmly fix the intermediate plate 150. This configuration increases the complexity of a fabrication process. In addition, due to the added structures, the gas may fail to be dispersed in the lateral direction rapidly and reliably.
FIG. 2 illustrates another type of showerhead of the related art. The showerhead illustrated in FIG. 2 has two intermediate plates, i.e. a first intermediate plate 151 and a second intermediate plate 152, unlike the showerhead of FIG. 1 having a single intermediate plate. The interior space of a body 100 is divided into a first dispersion chamber 111, a second dispersion chamber 112, and a distribution chamber 120 along a vertical direction. Two gas supply parts are provided, unlike the showerhead of FIG. 1 in which a single gas supply is provided. A first gas supply part 131 is disposed in the first dispersion chamber 111, and a second gas supply part 132 is disposed in the second dispersion chamber 112.
A plurality of connecting holes 171 are formed in the intermediate plates 151 and 152. A plurality of first dispersion pins 161 are fitted into portions of the connecting holes 171 in the second intermediate plate 152 such that the plurality of first dispersion pins 161 extended from the second intermediate plate extend through the second dispersion chamber 112 and through the connecting holes 171 in the first intermediate plate 151 to protrude upwardly from the first intermediate plate 151. A plurality of second dispersion pins 162 are fitted into the remaining portions of the connecting holes 171 in the second intermediate plate 152 such that the plurality of second dispersion pins 162 protrude upwardly from the second intermediate plate 152.
The first gas supplied to the first dispersion chamber 111 through the first gas supply part 131 is uniformly dispersed in a lateral direction within the first dispersion chamber 111 for a short period of time, influenced by the first dispersion pins 161, before being uniformly introduced to the distribution chamber 120 through the first dispersion pins 161. On the other hand, second gas supplied to the second dispersion chamber 112 through the second gas supply part 132 is uniformly dispersed in a lateral direction within the second dispersion chamber 112 for a short period of time, influenced by the second dispersion pins 162, before being uniformly introduced to the distribution chamber 120 through the second dispersion pins 162.
Consequently, the first gas and the second gas are uniformly mixed across the entire area within the distribution chamber 120, and the mixture gas having uniform pressure is subsequently expelled downwardly through injection holes 170.
However, like the showerhead of FIG. 1, this showerhead also requires spacers 181 and 182 to be disposed within the first dispersion chamber 111 and the second dispersion chamber 112 in order to firmly fix the intermediate plates 150, which is problematic as same.
FIG. 3 illustrates a further type of showerhead of the related art. The showerhead illustrated in FIG. 3 is configured such that two showerheads as illustrated in FIG. 2 are stacked on each other in a top-bottom direction. Injection tubes 140 extend downwardly from injection holes 170 in the upper showerhead, and the lower showerhead has guide tubes 145 through which the injection tubes 140 of the upper showerhead can extend.
With this configuration, the first gas and the second gas introduced to the upper showerhead may be uniformly distributed within a distribution chamber 120 and subsequently expelled onto a substrate (not shown) from the injection tubes 140 extending through the lower showerhead. On the other hand, the first gas and the second gas introduced to the lower showerhead may be uniformly distributed within the distribution chamber 120 and subsequently expelled downwardly through injection tubes 140 in the same manner.
Here, the first and the second gases introduced to the upper showerhead may be same as or different from the first and second gases introduced to the lower showerhead depending on intended purposes.
In this case, however, spacers 181 and 182 may be still disposed as shown in FIG. 2.
As described above, the showerheads of the related art require the spacers 180, 181, and 182 to be disposed in order to firmly fix the intermediate plates 150, 151, and 152. When gases are dispersed in a lateral direction within the dispersion chambers 110, 111, and 112, the spacers 180, 181, and 182 act as obstacles. Consequently, the gases fail to disperse rapidly and reliably, which is problematic.